The main purpose of this combined core is to provide a comprehensive service using state-of-the-art molecular and genetic methods to generate a variety of sophisticated knock-in, knock-out and transgenic mice for DRC investigators in their type 1 and type 2 diabetes research. We have successfully generated many lines of knock-in, knock-out and transgenic mice related to diabetes studies. It is noteworthy three ofthe highlights among all the animals generated during the previous funding cycle. Firstly, humanized mice, which carry 5 human genes by sequential re-targeting the same ES cells. The engraftment of human fetal liver-derived CD34+ hematopoietic stem cells can reach nearly 100% and last up to 9 months in this humanized mouse. Secondly, lines of innate immunity deficient NOD mice for the studies of type 1 diabetes, especially in association with exogenous and endogenous environmental factors. Using MyD88 deficient NOD mice generated by the core, DRC investigators demonstrated the importance of commensal flora in type 1 diabetes development and gut flora is an environmental modifier that influence diabetes onset Thirdly, lines of inflammsome deficient B6 mice for the studies of metabolic syndrome and type 2 diabetes. DRC investigators found that inflammasomes NLRP3 and NLRP6 negatively regulate NAFLD progression and obesity via modulation ofthe gut flora. This combined core consists of three subcores - Molecular, Gene targeting and Mouse breeding (MGM) components. Each subcore has its distinct function while all is interconnected. We will continue to provide our outstanding service for Yale DRC community. Moleculai: subcore will increase the use of improved high efficiency BAC mutagenesis to facilitate the generation of customized constructs for both type 1 and type 2 diabetes studies. Together with Molecular subcore. Gene targeting subcore will extend the humanized mouse model systems to include diabetes-related genes in order to evaluate preclinical testing of new therapies and/or vaccines, by our DRC investigators, for treatment and prevention type 1 diabetes. Mouse breeding subcore will backcross the improved humanized mouse lines to NOD background and several lines of infammasome deficient mice to pure NOD background forthe studies of type 1 diabetes.